Dissolved oxygen & oxygen saturation percentage (GBR4 BGC v4.2 baseline)
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Data gap notice
Some dates in the 4km eReefs BioGeoChemical model v4.2 dataset have been removed because the model output for those dates was found to be inaccurate, as shown in this sample video.
The following date ranges have been removed:
| Start date | End date |
|---|---|
| 2 Jan 2011 | 31 Jan 2011 |
| 2 Feb 2012 | 2 Mar 2012 |
| 9 Mar 2013 | 7 Apr 2013 |
| 1 Mar 2014 | 30 Mar 2014 |
| 6 Apr 2015 | 5 May 2015 |
| 10 May 2016 | 8 Jun 2016 |
| 14 Jun 2017 | 13 Jul 2017 |
| 19 Jul 2018 | 17 Aug 2018 |
| 23 Aug 2019 | 21 Sep 2019 |
| 26 Sep 2020 | 25 Oct 2020 |
| 31 Oct 2021 | 29 Nov 2021 |
| 19 May 2022 | 17 Jun 2022 |
Please use caution when interpreting the videos in the player above.
Although the obviously inaccurate dates have been removed, the model may take some time to recover after each disruption. As a result, data in the days and weeks following the removed periods may also be affected. The 30-day buffer used here is a visual estimate and not scientifically validated, so some remaining inaccuracies may still be present in the dataset.
We will update this portal when corrected model output becomes available.
Dissolved Oxygen
Concentration of oxygen.
Dissolved oxygen plays a pivotal role, driving multiple biogeochemical processes and influencing the balance of other elements like carbon, nitrogen, and phosphorus. The BGC model cycles carbon, nitrogen, phosphorus and oxygen through multiple phytoplankton, zooplankton, detritus and dissolved organic and inorganic forms in the water column and sediment layers.
The production (by photosynthesis) and consumption (by respiration and remineralisation) of dissolved oxygen is included in the model and, depending on prevailing concentrations, facilitates or inhibits the oxidation of ammonium to nitrate and its subsequent denitrification to dinitrogen gas which is then lost from the system.
More detail on how oxygen levels were modelled can be found in Baird et al. (2020).
Oxygen saturation percentage
The saturation state of oxygen [O2]sat is determined as a function of temperature and salinity following Weiss (1970). It represents the maximum amount of the dissolved oxygen that the water can hold. It is used to calculate the amount of oxygen exchange in the sea-air boundary. If the oxygen saturation percentage is below 100% then oxygen will be absorbed from the atmosphere. If it is above 100% then oxygen will be out-gassed from the sea into the atmosphere.
Reference
Baird, M. E., Wild-Allen, K. A., Parslow, J., Mongin, M., Robson, B., Skerratt, J., Rizwi, F., Soja-Woźniak, M., Jones, E., Herzfeld, M., Margvelashvili, N., Andrewartha, J., Langlais, C., Adams, M. P., Cherukuru, N., Gustafsson, M., Hadley, S., Ralph, P. J., Rosebrock, U., … Steven, A. D. L. (2020). CSIRO Environmental Modelling Suite (EMS): scientific description of the optical and biogeochemical models (vB3p0). Geoscientific Model Development, 13(9), 4503–4553. https://doi.org/10.5194/gmd-13-4503-2020
Weiss, R.: The solubility of nitrogen, oxygen and argon in water and seawater, Deep Sea Res., 17, 721–735, 1970.
Source data
The videos/images on this page are based on the 4km eReefs BioGeoChemical model (v4.2) run with SOURCE Catchments using Baseline catchment conditions. The model builds on the CSIRO Environmental Modelling Suite (EMS), described in the paper: Scientific description of the optical and biogeochemical models (vB3p0). The dataset metadata is available from the NCI GeoNetwork: eReefs GBR4 Biogeochemistry and Sediments v4.2 baseline catchment scenario. The raw model data is available from the NCI THREDDS server (daily, in curvilinear NetCDF format).
Data span
These results are based on a fixed time period (Dec 2010 - Apr 2019) hind-cast analysis developed for comparing changes in land practices. The river runoff used to drive the BGC model was provided by the SOURCE Catchments modelling.